Saddle soap is safe for most leathers. Be sure to oil up the chaps again afterward, may not have to bother oiling the jacket. I clean my chaps only when I need to oil them up, which is not very often; the jacket has never been cleaned in 13 years. Nothing looks worse than new leather, followed a close second by clean leather...
+1 on the saddle soap. I prefer the bar type with a medium bristle brush. Follow up with Dubbins or something similar to recondition and waterproof the leather.
I use maguires premimum leather wipes, they come in a pop up container and do a good job of cleaning the dried bugs without making the leather look shinny.
Get some saddle soap and a good plastic bristle brush if it's actual leather...once you soap it up then just use a good leather treatment and wipe it down.